Seminar Topic - Adaptive Piezoelectric Energy Harvesting Circuit

The need for a wireless electrical power supply has spurred an interest in piezoelectric energy harvesting, or the extraction of electrical energy using a vibrating piezoelectric device. A vibrating piezoelectric device differs from a typical electrical power source in that its internal impedance is capacitive rather than inductive in nature.

The objective of the research described herein was to develop an approach that maximizes the power transferred from a vibrating piezoelectric transducer to an electromechanical battery. 

 

This paper presents an adaptive approach to harvesting electrical energy from a mechanically excited piezoelectric element. The dc-dc converter with an adaptive control algorithm harvested energy at over four times the rate of direct charging without a converter. Furthermore, this rate is expected to continue to improve at higher excitation levels.

The flexibility of the controller allows the energy harvesting circuit to be used on any vibrating structure, regardless of excitation frequency, provided a piezoelectric element can be attached. Also, external parameters such as device placement, level of mechanical vibrations or type of piezoelectric devices will not affect controller operation. The control algorithm can also be applied to other dc-dc converter topologies. This would allow the development of optimized designs based upon the expected excitation or the electronic load that is to be powered. Future work will focus on the design of an optimized system design using standalone control circuitry.